Abstract Book

ESTRO 37

S438

OS were 91.7%, 87.4% and 75.1% respectively for re- excised, primary and recurrent STS; p: 0.015. Conclusion The results of this analysis confirm those observed in other studies showing that a combination of BT and EBRT is able to produce high LC and OS rates. Prospective studies on the use of BT/EBRT with uniform radiation doses and large patient population in the adjuvant setting of STS are still needed to define the optimal treatment schedule.

problems and Xersostomia were reported in 9.1% and in 6.8% respectively. Endocrinopathis and hearing defects were reported each in 9.1% of patients.

Poster: Clinical track: Paediatric tumours

PO-0839 Treatment outcome and prognostic factors of pediatric parameningeal rhabdomyosarcoma: NCI experience M. Mortada 1 , E. Khalil 1 , A. Sakr 2 , R. Emad 1 1 Egyptian National Cancer Institute- Cairo University, Radiation Oncology, Cairo, Egypt 2 Kasr Al-Aini Center of Clinical Oncology and Nuclear Medicine NEMROCK- Faculty of Medicine- Cairo University, Clinical Oncology, Cairo, Egypt Purpose or Objective To assess local control rate and calculate the overall survival (OS) and progression free survival (PFS) of pediatric parameningeal rhabdomyosarcoma (PM-RMS) patients treated at National Cancer Institute, Cairo University, Egypt between 2005 and 2014 and to examine the possible prognostic factors affecting treatment outcome. Material and Methods A retrospective study in which medical records of 44 pediatric patients newly diagnosed with PM-RMS between 2005 and 2014 were reviewed. The rate of local control was determined as well as the overall survival and the progression free survival. Prognostic factors (such as age at diagnosis, pretreatment hemoglobin level, intacranial extension (ICE), histology subtype, IRSG stage, response to chemotherapy, radiation therapy overall treatment period (OAP) and tumor response at end of treatment) and their effect on survival were studied. The rate of late complications was assessed. Results Median age was 7 years (range: 1 to 20 years). Male to female ratio was 1.9:1. The commonest primary subsite was nasopharynx (29.6%) followed by maxilla (20.5%) and infratemporal fossa (18.2%). Embryonal RMS was the most common pathological subtype (63.6%). Intracranial extension (ICE) was reported in 31.8% of cases. IRSG stage 3 constituted 75% of cases. All patients were treated by systemic CTH (VAC) then RTH was adopted at week 0 – 4 in case of ICE and at week 12 in the absence of ICE. Radiotherapy was the local treatment modality in 39 cases and 2 patients underwent surgery followed by radiotherapy postoperatively while 2 patients underwent surgery only and one patient died due to disease progression after receiving induction chemotherapy. Median RTH dose was 5040 cGy and median overall treatment period (OAP) was 47 days. 3D conformal radiotherapy was the main radiotherapy technique and only 5 patients were treated by IMRT. Complete response was reported in 75% of cases. The 5 year OS and PFS rates were 50% and 43.8% respectively. Factors which statistically affected survival (P < 0.05) on univariate analysis included age at diagnosis, T stage, pretreatment Hemoglobin %, (ICE), (OAP) and treatment response at week 40 while on multivariate analysis T stage, (OAP) and treatment response were the independent factors affecting survival. Regarding late radiation effects, chronic sinusitis was reported in 20.5% of patients. Cataract was reported in 11.4% of patients Dental

Conclusion PM RMS still represents a challenge for the radiation and pediatric oncologist. The results are comparable to other national and international studies. Combined modality is the current standard treatment and radiotherapy is an integral component in the management of PM-RMS. Prognostic factors affecting survival include age at diagnosis, T stage, pretreatment Hemoglobin %, (ICE), (OAP) and treatment response at week 40. PO-0840 Impact of irradiating residual disease to 30Gy on OAR dose in pediatric mediastinal Hodgkin lymphoma B. Hoppe 1 , N.P. Mendenhall 1 , E. Sandler 2 , W. Slayton 2 , M.J. Joyce 2 , S. Flampouri 1 1 University of Florida College of Medicine, Radiation Oncology, Jacksonville, USA 2 University of Florida College of Medicine, Pediatrics, Jacksonville, USA Purpose or Objective The predominant pattern of relapse among patients with pediatric Hodgkin lymphoma (pHL) receiving chemotherapy followed by 21Gy of radiotherapy (RT) is in-field. Among adult patients with Hodgkin lymphoma receiving 30-36 Gy of RT, the pattern of relapse shifts to more out-of-field relapses. The present study investigates changes in dose to the organs at risk (OARs) if an